Electric shutter control circuitry

ABSTRACT

First and second switches each having respective first and second switch positions establish shutter control by either a fixed timing circuit or a brightness measuring circuit in accordance with the setting of a distance adjustment ring. The contacts of the switches are mounted on a rotatable change over ring and the distance adjustment ring. The change over ring includes means for setting the flash guide number.

United States Patent Hayashi [4 1 June 13, 1972 4] ELECTRIC SHUTTERCONTROL [561 References Cited C IRC UITRY UNITED STATES PATENTS 7Inventor: Tmhio m Osaka. p n 3,535,989 10/1970 Kitai ..95/53 EB x 73Assi nee: Minolta Cum" Kabu'hnd Kim" 3,478,660 11/1969 Land ..95/53 E XI 1 g Minambk'u' Osaka, Japan 3,504,604 4/1970 Kitai ..95/10 C Filed:1970 Primary ExaminerSamuel 5. Matthews [2!] App], No; 66,766 AssistantExaminer--Robert P. Greiner Attorney-Watson, Cole, Grindle & WatsonABSTRACT Foreign Application Priority Data First and second switcheseach having respective first and Aug. 29, 1969, Japan ..44/68755 secondswitchtpositions establish u control y either a fixed timing circuit ora brightness measuring circuit in ac- [52] U.S. Cl ..95/1l R, 10 C,95/53 E cordance with the setting of a distance adjustment ring. The[51] Int. Cl. ..G03b 7/16 contacts of the switches are mounted on arotatable change [58] Field of Search ..95/l1 R, 53 E, 53 EA, 53 EB,over ring and the distance adjustment ring. The change over 95/ 1 1.5 R,10 C ring includes means for setting the flash guide number.

4 Claims, 2 Drawing Figures I 8 l3 l2 IO 1 l4 M! I l5 0:81.? 2:5 lp emgl g A l I 18 9 (F2) .1; e 19(A2) l f if! 14 2'0 I 6 F1 AI 23 ELECTRICSHUTTER CONTROL CIRCUITRY BACKGROUND OF THE INVENTION tion of anelectric shutter can be changed over to the exposure controlcorresponding to the brightness of an object (hereinafter this is calledas EE exposure control) and to an exposure control in accordance with afixed exposure time. However, when the photographic distance is at alarge range, even though the diagram is fully opened flash photographyis impossible; In such a case a warning lamp is lit or the release lockof the shutter is efi'ected'so as to prevent an exposure. However, it isdesirable to effect shutter operation in such in stances and thecircuitry of the present invention enables a photograph to be taken.

SUMMARY OF THE INVENTION:

The primary object of the present invention is to provide a changeoverdevice for operating an electric shutter, which even in the case ofwhere the electric shutter is set to control the exposure time suitablefor a flash photograph, automatically to effect EE exposure control byinterlocking with the distance adjusting member of a camera if thedistance is unsuitable for a flash photograph and effect a long timeexposure through EE exposure control.

Further another object of the present invention is to provide a changeover device for operating an electric shutter, which is adapted foroperation of an automatic changeover member for interlocking with aphotographing distance adjusting member and also interlocking with thesetting of the guide number for a flash bulb.

Furthermore, another object of the present invention is to provide achangeover device for operating an electric shutter, which gives awarning when a changeover member is set on the flash photograph side andan automatic changeover member is changed over for BB photography inaccordance with the setting up a distance adjustment member.

The above and other objects of the present invention will be moreclearly understood from the embodiment described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS portion of the changeover device foroperating an electric shutter in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of anelectric circuit of a changeover device for operating an electricshutter in accordance with the present invention, wherein power source 1and main switch 2 are closed at the first stage of the release operationand are connected to condenser C and timing switch 4 to whichphotoconductive element 5 and fixed resistance 6 are connected inparallel to each other so as to form a time constant circuit, throughsetup switch 7 and automatic changeover switch 8 which interlocks withdistance adjusting ring 11 (see FIG. 2). And, the connection point ofthe time constant circuit is connected to the base of first transistor Tand the collector of first transistor T is connected to the base ofsecond transistor T so as to form a Schmitt trigger switching circuit.In the collector of second transistor T, is an electromagnet 3 forrestraining the starting of the shutter closmg.

Changeover switch 7 is provided with two contacts A, and F and when onthe contact A the time constant circuit composed of photoconductiveelement 5 and condenser C is'connected to power source 1 and main switch2, and when the changeover switch 7 is on the contact F it is connectedto automatic changeover switch 8 and interlocked with distance adjustingring 11.

Automatic change over switch 8 also is provided with two contacts A andF and when on the contact A in the same.

manner as contact A1 for change over switch 7, the time constant circuitcomposed of photoconductive element 5 and condenser C is connected topower source I and mainswitch 2, and when automatic change over switch 7is on the contact F the time constant circuit of fixed resistance 6 andcondenser C is connected to power source 1 and main switch 2 as long asautomatic set up switch 7 is on the contact F The relative constructionbetween the mechanical structure including the interlocking mechanism ofdistance adjusting ring 11 and automatic changeover switch 8, and theelectric.

circuit is shown in FIG. 2, wherein on fixed lens barrel 9 distanceadjusting ring 11 is rotatably mounted, and when'the photographicdistance is adjusted by means of index 12. and range marker 10 on fixedlens barrel 9 movable lens barrel l4 moves back and forth to adjust thefocus of an objective lens as is well known in the art.

On the internal circumference of distance adjustingring 11 ring 13 ismounted, and on ring 13 contact piece 8' for automatic changeover switch8 is provided through insulating plate 15 and connected to contact F lfor changeover switch 7 mounted on the camera body side through a leadwire.

Further, on the inside of fixed lens barrel 9 ring 16 is provided andthrough insulating plate 17 on ring 16 contact plate 18 and contactplate 19, which are parallel and insulated from each other are mounted.Contact plate 18 on the short range side of range marker 10 is connectedto fixed resistance 6 by a lead wire to form contact F and contact plate19 on the long range marker side forms contact A; connected tophotOconductive element 5 by a lead wire through pilot lamp 23 describedlater. Contact piece 8 slides on contact plates 18, 19 to contact withone or the other in accordance with the rotation of distance adjustingring 11.

When a flash bulb having a guide number is used ring 16 can be fixed tofixed lens barrel 9, however, ring 16 is arranged to i be rotatablerelative to fixed lens barrel 9 so as to accommodate flash bulbs havingdifferent guide numbers. In order to facilitate the rotation of ring 16,knob and index 22 is provided projecting from transverse slot 21 formedon lens barrel 9, so as to face guide number scale 22 on lens barrel 9.

Since the present invention is formed as described above, when taking aphotograph in daylight changeover switch 7 is connected to the contactA. And thus, simultaneously with the release operation, first, mainswitch 2 is closed and electromagnet 3 for restraining the closingoperation of the shutter is operated, and then simultaneously with theopening of the shutter timing switch 4 is opened and condenser C ischarged by the electric current running though photoconductive element5. And, when condenser C reaches a threshold voltage both transistors Tand T are switched and electromagnet 3 is demagnetized to start theshutter closing operation, and accordingly the EEphotogi-aph is efiectedin accordance with the brightness of an object.

And, when taking a flash photograph, first, knob 20 is set to the guidenumber scale for the flash bulb being used, and then changeover switch 7is put on contact F and distance adjusting ring 11 is adjusted tocorrespond to the correct photographic distance. In this case, when thedistance is short and within the range possible to take a flashphotograph, automatic changeover switch 8 comes into contact withcontact plate 18 and accordingly contact F is connected sothat the timeconstant circuit composed of fixed resistance 6 and conthe shutterclosing operation, and through the subsequent release operation timingswitch 4 is opened simultaneously with the shutter opening operation andcondenser C is charged by the power current running through fixedresistance 6. And, when condenser C reaches a threshold voltage, in thesame manner as described hereinbefore the switching circuit is reversedand electromagnet 3 is demagnetized to start the shutter closingoperation. In this case, the resistance value of fixed resistance 6 isset so that the delay time may be one-thirtieth second which is suitablefor a flash photograph;

In that situation, however, when the distance is long contact piece 8'of automatic changeover switch 8 moves from contact plate 18 (contact Fto contact plate 19 (contact A and fixed resistance 6 is disconnected,and instead photoconduc-' tive element and condenser C are connected.Therefore, the exposure time in this case is long as a matter of course,however, the proper exposure for a dark object is effected.

By the way, in the embodiment circuit shown in FIG. 2, in

the circuit connecting contact plate 19 to photoconductive element 5pilot lamp 23 is inserted, and by means of lighting the photographer iswarned the long exposure so as to prevent the camera from shaking,swinging, etc..

lclaim:

1. A shutter control circuit for a photographic camera, comprising:

a distance adjusting member;

an automatic changeover member mounted adjacent said distance adjustingmember;

a brightness measuring circuit including a photoconductive element and acondenser connected in series with one another;

a resistance connected to said condenser in series for establishing ashutter speed suitable for flash photography;

a first switch and a second switch each having first and second contactpositions, said first positions of said first and second switchesactuating said resistance and condenser to establish a fixed shutterdelay;

said first switch in said first position and said second switch in saidsecond position actuating said brightness measuring circuit to controlthe actuation of said shutter in accordance with the brightness of theobject; said first switch in said second position controlling theactuation of said shutter in accordance with the brightness of theobject; said first switch is actuated manually and said second switch ispositioned by said automatic changeover member and said distanceadjusting member.

2. A shutter control circuit as set forth in claim 1, wherein saidautomatic changeover member includes means for setting a flash guidenumber, and further including a contact connected to saidphotoconductive element and a contact connected to said resistance; andsaid distance adjusting member includes a movable contact engageablewith said contacts of said change over member for establishing saidfirst and second switch positions.

3. A shutter control circuit as set forth in claim 1, furthercomprising:

a pilot lamp connected to said photoconductive element and actuated withsaid first switch and said second switches in said second positions andsaid distance adjustment member set to a distance indicatingflashineffectiveness. I

4. A shutter control circuit as set forth in claim 1, wherein saiddistance adjusting member is composed of a distance adjusting ringrotatable about the fixed lens barrel of the camera,

and said automatic changeover member is rotatable about said fixed lensbarrel and composed of a ring having a guide number indicator, andcontact members mounted on said changeover ring respectively connectedto said photoconductive element and said resistance.

1. A shutter control circuit for a photographic camera, comprising: adistance adjusting member; an automatic changeover member mountedadjacent said distance adjusting member; a brightness measuring circuitincluding a photoconductive element and a condenser connected in serieswith one another; a resistance connected to said condenser in series forestablishing a shutter speed suitable for flash photography; a firstswitch and a second switch each having first and second contactpositions, said first positions of said first and second switchesactuating said resistance and condenser to establish a fixed shutterdelay; said first switch in said first position and said second switchin said second position actuating said brightness measuring circuit tocontrol the actuation of said shutter in accordance with the brightnessof the object; said first switch in said second position controlling theactuation of said shutter in accordance with the brightness of theobject; said first switch is actuated manually and said second switch ispositioned by said automatic changeover member and said distanceadjusting member.
 2. A shutter control circuit as set forth in claim 1,wherein said automatic changeover member includes means for setting aflash guide number, and further including a contact connected to saidphotoconductive element and a contact connected to said resistance; andsaid distance adjusting member includes a movable coNtact engageablewith said contacts of said change over member for establishing saidfirst and second switch positions.
 3. A shutter control circuit as setforth in claim 1, further comprising: a pilot lamp connected to saidphotoconductive element and actuated with said first switch and saidsecond switches in said second positions and said distance adjustmentmember set to a distance indicating flash ineffectiveness.
 4. A shuttercontrol circuit as set forth in claim 1, wherein said distance adjustingmember is composed of a distance adjusting ring rotatable about thefixed lens barrel of the camera, and said automatic changeover member isrotatable about said fixed lens barrel and composed of a ring having aguide number indicator, and contact members mounted on said changeoverring respectively connected to said photoconductive element and saidresistance.